The present invention relates to a structure of a transformer bobbin assembly, and more particularly to a structure of a transformer bobbin assembly having multiple step pin rows.
The typical structure of a transformer assembly includes a magnetic core, a bobbin, a primary coil, a secondary coil and a plurality of pin leads. The primary coil and the secondary coil are separately wound on the bobbin and coupled electromagnetically through the magnetic core. The plurality pin leads are divided into two types, i.e. the primary pin leads and the secondary pin leads. The ends of the primary coil and the secondary coil are usually soldered onto the primary pin leads and the secondary pin leads, respectively.
FIG. 1 shows a perspective view of a traditional transformer bobbin. This bobbin 1 includes a cylinder 10, a primary base 11, a secondary base 12, a plurality of primary pin leads 111 disposed in the primary base 11 and a plurality of secondary pin leads 112 disposed in the secondary base 12. For safety regulations, the necessary creepage and clearance distances are always taken into consideration in order to make sure the primary winding coil and the secondary winding coil are not shorted. The requirement of creepage and clearance was met by adding some insulation tapes. The term xe2x80x9ccreepagexe2x80x9d indicates the minimum distance along a surface of insulation between the primary winding coil and the secondary winding coil. The term xe2x80x9cclearancexe2x80x9d indicates the minimum distance between the primary winding coil and the secondary winding coil through air. Referring to FIG. 2, three layers of insulation tapes are applied for isolation and insulation. The transformer bobbin 1 further includes a primary winding coil 21, a secondary winding coil 22 and a magnetic core (not shown) located within the cylinder 10. The secondary winding coil 22 is wrapped by a first insulation tape 31 and then isolated by a second insulation tape 32. The primary winding coil 21 is then wound on the bobbin 1 over the second insulation tape 32 and wrapped with a third insulation tape 33. The third insulation tape 33 is also called the marginal tape, which is needed for isolation among the primary pin leads 111, the secondary pin leads 122, the primary winding coil 21 and the secondary winding coil 22. Generally, a tube (not shown) is used to cover the end of the primary coil 21 and the end of the secondary coil 22 for isolation with the magnetic core. It is apparent that the process for manufacturing such transformer is very labor-intensive and complicated. Moreover, the winding window is limited since the three insulation layers 31, 32 and 33 occupy some space. The structure of such transformer assembly results in an increasing inductance leakage due to the addition of the three insulation layers 31, 32 and 33; thus, the electric performance is decreased.
Therefore, the present invention provides an improved structure of a transformer bobbin assembly for overcoming the problems described above.
It is an object of the present invention to provide a structure of a transformer bobbin having multiple step pin rows for deleting the marginal tape, the insulation tape and the tube which are necessary for the traditional transformer.
In accordance with one aspect of the present invention, the structure of the transformer bobbin could meet the minimum creepage and clearance distance requirements. The transformer bobbin includes a cylinder, a primary base and a secondary base connected to the cylinder, a plurality of primary pin leads disposed in a row and on the primary base, a plurality of secondary pin leads disposed in multiple step rows and on the secondary base.
In accordance with another aspect of the present invention, the secondary pin leads are disposed in two step rows, i.e. the first step row and the second step row. Each of the first step row pin leads is used for supporting the secondary base. The secondary pin leads in the first step row can be kicked out, and at least two secondary pin leads are disposed in the second step row. Certainly, the secondary base can further include at least two cavities.
It is another object of the present invention to provide a transformer bobbin. The transformer bobbin includes a cylinder, a primary base and a secondary base connected to the cylinder, a plurality of primary pin leads disposed in multiple step rows and on the primary base, a plurality of secondary pin leads disposed in a row and on the secondary base.
It is another object of the present invention to provide a transformer bobbin assembly having multiple step pin rows for deleting the marginal tape, the insulation tape and the tube which are necessary for the traditional transformer.
The transformer bobbin assembly according to the present invention includes a cylinder, a magnetic core located within the cylinder, a primary winding coil and a secondary winding coil separately wound on the cylinder, a primary base and a secondary base connected to the cylinder, a plurality of primary pin leads disposed in a row and on the primary base, a plurality of secondary pin leads disposed in multiple step rows and on the secondary base, wherein both ends of the secondary winding coil are connected to at least two of the secondary pin leads for providing a predetermined minimum creepage and clearance distance, and a core shield placed over the ends of the cylinder for isolation among the magnetic core, the primary winding coil and the secondary winding coil.
Preferably, the multiple step rows includes a first step row and a second step row. Each of the secondary pin leads disposed in the first step row is used for supporting the secondary base. Preferably, at least two of the secondary pin leads are disposed in the second step row.
Certainly, the secondary base can further include at least two cavities for facilitating winding the both end of the secondary winding coil onto the two secondary pin leads in the second step row therethrough.
It is another object of the present invention to provide a transformer bobbin assembly.
The transformer bobbin assembly according to the present invention includes a cylinder, a magnetic core located within the cylinder, a primary winding coil and a secondary winding coil separately wound on the cylinder, a primary base and a secondary base connected to the cylinder, a plurality of primary pin leads disposed in multiple step rows and on the primary base wherein both ends of the primary winding coil are connected to at least two of the primary pin leads for providing a predetermined minimum creepage and clearance distance, a plurality of secondary pin leads disposed in a row and on the secondary base, and a core shield placed over the ends of the cylinder for isolation among the magnetic core, the primary winding coil and the secondary winding coil.
The transformer bobbin assembly according to the present invention has the advantages of less producing cost, less space occupied, simpler manufacturing process, easier winding and less leakage inductance.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: